JP2011052574A - Valve bridge of valve gear - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a valve bridge of a valve gear which enhances wear resistance and reliability and realizes weight reduction with simple constitution. <P>SOLUTION: Valve abutment surfaces 2 are smoothly formed on respective undersurfaces at one end and the other end of a valve bridge 1, and force an upper end surface 13a of a valve to abut thereon, respectively. Rocker arm abutment surface 3 is smoothly formed on a central top surface of the valve bridge 1 and makes the rocker arm 6 abut thereon. The bank parts 4 are extended downward to the center sides in the peripheries of respective valve abutment surfaces 2 to secure inner dimensions of the valves. End sides in peripheries of respective valve abutment surfaces 2 are opened in a horizontal direction up to an outer end 1a of the valve bridge 1. Thrust loads imparted onto respective valves are dispersed by slide in a horizontal direction between the rocker arm 6 and valve bridge 1. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a valve bridge of a valve operating mechanism interposed between a rocker arm and a pair of valves.

  Conventionally, in a valve mechanism of an internal combustion engine, a guideless valve bridge is interposed between a rocker arm and a pair of valves so as to open and close the pair of valves simultaneously. Yes. For example, in Cited Document 1, a valve drive in which upper ends of a pair of valves (two valve rods) are engaged with both ends of a valve bridge and a rocker arm (valve arm) is in contact with the upper surface of the central portion of the valve bridge. A mechanism is disclosed. In this technique, holding the valve bridge without a guide rod can ensure the stability and smoothness of the valve operation while simplifying the structure.

On the other hand, the valve of the internal combustion engine reciprocates on a predetermined linear path, whereas the rocker arm swings about the rocker shaft. Therefore, the posture of the valve bridge interposed between them tends to be inclined obliquely with respect to the sliding direction of the valve, and there is a problem that the followability of opening and closing of the valve with respect to the movement of the valve bridge is likely to deteriorate.
In response to such a problem, for example, Patent Document 2 describes a valve operating mechanism for an engine in which the distance between the abutted surfaces of the valve bridges with respect to the respective valves is provided in a freely adjustable manner. In this technique, a slider that is slidable to the left and right is provided on the lower surface of the valve bridge, and one of a pair of valves is brought into contact with the slider, and the other valve is directly fixed to the valve bridge. With such a configuration, the upper end interval of the pair of valves can be adapted to stabilize the posture of the valve bridge, and the valve lift amounts of the pair of valves can be made uniform.

JP 2001-152816 A JP 2006-152911 A

  However, in the conventional technique described in Patent Document 2, it is only possible to adjust the support interval between the pair of valves in the valve bridge, but the sliding amount in the left-right direction of each valve cannot be made uniform. . That is, only one valve abutting the slider is allowed to move in the left-right direction, and the other valve directly fixed to the valve bridge is restrained from moving, so the upper end of the valve Thrust load is concentrated. Therefore, there is a problem that the other valve and the upper end of the stem guide are easily worn and the durability is lowered.

In the technique of Patent Document 2, one valve is brought into contact with the valve bridge via a slider. In other words, the structure requires a slider for each valve bridge, which increases the number of parts and increases the weight of the entire valve mechanism.
The present invention has been made in view of the above problems, and provides a valve bridge for a valve mechanism that has a simple configuration, excellent wear resistance, high reliability, and can be reduced in weight. The purpose is to provide.

  In order to achieve the above object, the valve bridge of the valve operating mechanism according to the first aspect of the present invention is a valve bridge of the valve operating mechanism interposed between the rocker arm and the pair of valves, one end and the other end. Are formed smoothly on the lower surface of each of the valves, and are formed smoothly on the upper surface of the center of the one end and the other end of the pair of valves, and contact the rocker arm. A rocker arm contact surface; and a bank portion extending downward on the rocker arm contact surface side around each of the valve contact surfaces, the rocker arm contact surface around each of the valve contact surfaces The opposite side is characterized in that it opens horizontally to the outer end of the valve bridge.

That is, the concentration of thrust load acting between each of the pair of valves and the valve contact surface is prevented by opening the outer end side of the valve bridge on the valve contact surface.
According to a second aspect of the present invention, the valve bridge of the valve operating mechanism according to the present invention has a configuration in which, in addition to the configuration according to the first aspect, the pair of valves are formed such that the upper end surfaces thereof are circular, and A semicircular surface formed in a semicircular shape having substantially the same radius as the upper end surfaces of the pair of bulbs, a first side having a diameter in the semicircular surface, and both ends of an arc in the semicircular surface Is formed in a rectangular shape having a second side having substantially the same size as the radius of the upper end surface extending perpendicularly to the first side, and is formed of a rectangular surface disposed adjacent to the semicircular surface. It is characterized by having.

  Further, the valve bridge of the valve operating mechanism according to the third aspect of the present invention, in addition to the configuration according to the first or second aspect, extends vertically downward on the lower surface between the valve contact surfaces. The rib portion has a vertical dimension at the center of the one end and the other end, and is set to be larger than the dimension in the vicinity of the valve contact surface.

  According to the valve bridge of the valve operating mechanism of the present invention (Claim 1), the outer end opening surface is provided on the outer end side of the valve bridge with respect to the valve abutting surface to open the end portion, and the center side (the rocker arm abutting portion). By supporting the valve only on the surface side, the thrust load (load acting in the extending direction of the valve bridge) acting between the pair of valves and the valve bridge as the rocker arm swings is distributed to each valve. The amount of wear on the bank can be reduced, and the durability of the member can be increased. Further, since the load is distributed to each of the pair of valves, the margin for overrun of the valve operating mechanism can be improved. Furthermore, the weight can be reduced by opening the outer end side of the bank portion of the valve bridge.

  According to the valve bridge of the valve operating mechanism of the present invention (Claim 2), the valve contact surface is constituted by a semicircular surface having the same radius as the valve and a rectangular surface adjacent thereto, and the width of the rectangular surface. Since the dimension is formed to be the same dimension as the radius of the valve, the entire upper end surface of the valve can be contacted, and the movement of the valve bridge can be reliably transmitted to the valve. Further, for example, the length of the valve bridge in the longitudinal direction can be shortened, and the member can be further reduced in weight compared to the case where the valve contact surface has a long hole shape. Furthermore, it can process easily using tools, such as an end mill, and can reduce cost.

  Moreover, according to the valve bridge of the valve operating mechanism of the present invention (Claim 3), the cross-sectional performance can be improved by extending the rib portion on the lower surface between the valve contact surfaces, and the vertical direction Deformation against the load can be effectively suppressed. Moreover, the bending deformation | transformation about the extension direction of a valve bridge can be suppressed by setting the dimension of the perpendicular direction of a center part larger than the both ends side.

It is sectional drawing which shows the whole structure of the valve mechanism provided with the valve bridge which concerns on one Embodiment of this invention. It is a figure which shows this valve bridge, (a) is the side view, (b) is the bottom view. It is a figure which expands and shows the principal part of this valve bridge, (a) is a bottom view of a valve contact surface, (b) is a longitudinal cross-sectional view of the valve contact surface [A-A cross section of FIG. Fig.] (C) is a longitudinal sectional view of the rib portion (BB sectional view of Fig. 2 (b)). It is a side view for demonstrating operation | movement of the valve operating mechanism provided with this valve bridge, a continuous line shows the state at the time of valve closing, and a broken line shows the state at the time of the maximum lift of a valve.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[1. Overview Configuration]
FIG. 1 illustrates an OHV (overhead valve) type multi-cylinder diesel engine (internal combustion engine) to which a valve operating mechanism 10 according to the present invention is applied. Here, the outline of the cylinder block 28 is indicated by a two-dot chain line. A cylinder head 30 is fixed on the cylinder block 28, and an intake port 30a, an exhaust port, a water jacket 29, and the like connected to each cylinder are disposed therein. FIG. 1 is a cross section of one cylinder 27 of a plurality of cylinders arranged in a row in the cylinder block 28, cut along a plane perpendicular to the rotation axis of the crankshaft.

A pair of intake valves 7 and exhaust valves (not shown) are provided at the top of the cylinder 27, and the valve mechanism 10 opens and closes these valves. The device configuration for driving each of the intake valve 7 and the exhaust valve is substantially the same, and the details related to the intake valve 7 will be described in detail below.
FIG. 1 shows the valve operating mechanism 10 in a state where the intake valve 7 closes the intake port 30a. The vertical and horizontal directions in the following description are directions based on the arrangement position and orientation of each member described in FIG.

The valve operating mechanism 10 includes a camshaft 25, a push rod 23, a rocker shaft 18, a rocker arm 6, and a valve bridge 1 inside a rocker cover 20. The rocker cover 20 is a member fixed so as to cover the upper part of the cylinder head 30, and a space for accommodating each member of the main valve mechanism 10 is formed therein.
The camshaft 25 is a shaft member disposed in the cylinder block 28 or a crankcase located further below the cylinder block 28. The camshaft 25 is connected to the crankshaft via a power transmission mechanism (not shown), and rotates around the rotation axis O at an angular velocity corresponding to the rotational movement of the crankshaft.

  As shown in FIG. 1, an egg-shaped flat cam 26 whose distance from the rotation axis O to the peripheral surface 26a is not constant is fixed to the camshaft 25. The lower surface 24 a of the tappet 24 supported by the lower end portion of the push rod 23 is in contact with the peripheral surface 26 a of the flat cam 26. The push rod 23 is supported so as to be slidable in the vertical direction with respect to the cylinder head 30 and periodically reciprocates in the vertical direction according to the rotation angle of the camshaft 25. Note that the upward pressing force applied to the push rod 23 by the rotational movement of the camshaft 25 acts to rotate and rock the rocker arm 6 in the right direction in FIG.

  The rocker shaft 18 is a shaft member fixed to the cylinder head 30 via the bracket 19, and pivotally supports the rocker arm 6 on the outer cylinder surface thereof. The extending direction of the rocker shaft 18 is a direction perpendicular to the paper surface of FIG. Further, the interior of the rocker shaft 18 is formed hollow and functions as a flow path for lubricating oil supplied to various parts of the valve operating mechanism 10.

The rocker arm 6 includes a hollow cylindrical housing portion 16 that is pivotally supported by a rocker shaft 18, an arm portion 15 that extends in the left and right directions in FIG. 1 around the housing portion 16, and an adjustment screw fixing portion 17. It is prepared for. The housing portion 16, the arm portion 15, and the adjustment screw fixing portion 17 are integrally cast with cast iron.
The arm portion 15 of the rocker arm 6 is a portion formed so as to extend from the housing portion 16 in a direction substantially horizontal and perpendicular to the cylinder axis of the rocker shaft 18 (radial direction of the rocker shaft 18). The distal end portion of the arm portion 15 is formed to have a greater thickness in the vertical direction than the proximal end portion side. Further, the adjustment screw fixing portion 17 is a portion protruding from the side of the housing portion 16 opposite to the side on which the arm portion 15 extends.

An adjusting screw 17 a is fastened and fixed to the adjusting screw fixing portion 17. A cup end 22 fitted into the upper end portion of the push rod 23 is in contact with the lower end portion of the adjustment screw 17a. Thus, the rocker arm 6 swings around the rocker shaft 18 in accordance with the vertical reciprocation of the push rod 23.
The relative position between the adjustment screw 17a and the adjustment screw fixing portion 17 (that is, the contact position between the cup end 22 and the adjustment screw 17a) can be changed, whereby the rocking arm 6 swing start angle and end angle can be changed. Fine adjustment is possible. Note that the rocking width of the rocker arm 6 (the difference between the rocking start angle and the rocking angle) depends on the distance from the rotation axis O of the flat plate cam 26 to the peripheral surface 26a.

  On the other hand, the valve bridge 1 that supports the upper ends of the pair of intake valves 7 is in contact with the lower end surface 15 a of the distal end portion of the arm portion 15, and the rocker arm 6 is swung through the valve bridge 1. Communicate to each of them at the same time. The lower end surface 15a of the arm portion 15 is formed as a smooth cylindrical surface convex downward, and the surface is subjected to a hardening process such as a chill process. In addition, the curvature radius of the lower end surface 15a is R.

The valve bridge 1 is a rod-like member disposed substantially horizontally below the arm portion 15, and supports one intake valve 7 at each of both end portions in the extending direction of the valve bridge 1. The configuration of the pair of intake valves 7 is the same.
The intake valve 7 includes a valve stem 13, a spring seat 8, a valve spring 9, a stem guide 11 and a valve head 14. The valve head 14 is a valve body that opens and closes the intake port 30 a with respect to the cylinder 27. Further, the valve stem 13 is a shaft-shaped part formed integrally with the valve head 14 and is slidably supported with respect to the cylinder head 30 via the stem guide 11.

The stem guide 11 is a hollow cylindrical member fitted into the valve through hole 30b of the cylinder head 30 and supports the valve stem 13 therein. An oil seal 12 that seals the sliding contact surface between the stem guide 11 and the valve stem 13 is attached to the upper end portion of the stem guide 11.
Near the upper end of the valve stem 13, spring seats 8 that are in contact with both ends of the valve bridge 1 are fixed. Further, a valve spring 9 that biases the spring receiving seat 8 and the valve stem 13 upward is interposed between the spring receiving seat 8 and the upper surface of the cylinder head 30. The urging force applied to the spring seat 8 by the valve spring 9 is transmitted to the rocker arm 6 through the valve bridge 1 and acts to rotate the rocker arm 6 leftward in FIG.

[2. Configuration of valve bridge]
[2-1. Overall shape]
The configuration of the valve bridge 1 of the valve train 10 will be described in detail.
The valve bridge 1 includes a bridge main body portion 1b formed in a convex mountain shape with a central portion in the extending direction as a top portion, and a rib portion 5 provided below the bridge main body portion 1b. As shown in FIG. 2A, the overall shape of the valve bridge 1 is symmetrical with respect to the center line C.

  A valve contact surface 2 with which the upper end surface 13a of the valve stem 13 contacts is formed smoothly on the lower surfaces of the left and right ends in the extending direction of the bridge body 1b. The valve contact surface 2 is in surface contact with the upper end surface 13 a of the valve stem 13. In addition, a rocker arm abutting surface 3 that abuts against the lower end surface 15a of the arm portion 15 of the rocker arm 6 is formed smoothly at the center of the bridge body 1b. The rocker arm contact surface 3 is in line contact with the lower end surface 15 a of the arm portion 15, and the orientation of the contact line is a horizontal direction substantially perpendicular to the extending direction of the valve bridge 1.

As described above, the left and right ends of the valve bridge 1 are supported from below by the upper end surfaces 13 a of the two valve stems 13, and the central portion thereof is supported from above by the lower end surfaces 15 a of the arm portions 15 of the rocker arm 6. . The valve contact surface 2 and the rocker arm contact surface 3 are all horizontal.
[2-2. Rocker arm contact surface]
The contact position between the lower end surface 15 a of the arm portion 15 and the rocker arm contact surface 3 varies according to the rocker arm 6 swinging. For example, when the position of the valve bridge 1 is used as a reference, the lower end surface 15 a slides back and forth on the rocker arm contact surface 3 in the extending direction of the valve bridge 1. The width of the rocker arm contact surface 3 in the extending direction of the valve bridge 1 is set to be larger than the width in which the lower end surface 15a reciprocates.

FIG. 2A shows a position where the lower end surface 15a of the arm portion 15 and the rocker arm contact surface 3 are in contact with each other. Point D is the contact position when the intake valve 7 closes the intake port 30a, and point E is the contact position during maximum valve lift.
[2-3. Valve contact surface]
A bank portion 4 extending downward is formed around each valve contact surface 2. A circular outline of the valve stem 13 in a state where the upper end surface 13a is in contact with each valve contact surface 2 is indicated by a one-dot chain line in FIG. The radius of the upper end surface 13a of the valve stem 13 is r.

  The bank portion 4 is a portion having a horseshoe-like horizontal cross section, surrounds the side surfaces of the pair of valve stems 13 on the opposite surface side, and is on the rocker arm contact surface 3 side (that is, the center) around each valve contact surface 2. Side). The inner wall 4a of the bank portion 4 is in surface contact with the cylindrical surface 13b of the valve stem 13 and functions to support the valve stem 13 in the horizontal direction. That is, the horizontal movement of each valve stem 13 toward the center side of the valve bridge 1 is restricted.

On the other hand, the end side around each valve contact surface 2 is opened in the horizontal direction to the outer end 1 a of the valve bridge 1. Out of the cylindrical surface 13b of each valve stem 13, the outer end 1a side of the valve bridge 1 is not supported in the horizontal direction. That is, each valve stem 13 is allowed to move horizontally to the outside of the valve bridge 1.
The planar shape of the valve contact surface 2 will be described in detail. As shown in FIG. 3A, the valve contact surface 2 includes a semicircular surface 2a formed in a semicircular shape and a rectangular surface 2b adjacent thereto. The radius of the semicircle of the semicircular surface 2a is r, which is the same as the radius of the upper end surface 13a of the valve stem 13.

Further, the rectangular surface 2b is to match the long sides L ₁ length 2r to the site forming the diameter of the semicircular surface 2a, it forms a continuous contour arc semicircular surface 2a. The short side L ₂ of the rectangular surface 2b extends from both ends X ₁ and X ₂ of the arc of the semicircular surface 2a in a direction perpendicular to the long side L ₁ , and its length is approximately the same as r. (R + a, where a is a small value). As a result, the upper end surface 13 a of the valve stem 13 does not protrude from the valve contact surface 2, and the entire surface contacts the valve contact surface 2.

The inner wall 4a of the bank portion 4 is vertically suspended along the contour of the valve contact surface 2 having the above-described shape. Further, as shown in FIG. 2B, the distance F between the valve contact surfaces 2 at the left and right ends of the valve bridge 1 is the same as the allowable minimum distance when the intake valve 7 is assembled to the cylinder head 30. Is set.
[2-4. Rib]
As shown in FIG. 2A, a rib portion 5 extending vertically downward along the extending direction of the valve bridge 1 is provided below the bridge body portion 1b. As shown in FIG. 3 (c), the thickness t ₂ of the rib portion 5 is smaller than the thickness t ₁ of the bridge body portion 1b (t ₂ <t ₁₎ is set. In addition, the thickness here is a dimension in a direction that is horizontal and orthogonal to the extending direction of the valve bridge 1.

Further, the length of the rib portion 5 extending from the bridge main body portion 1b (vertical dimension) is set to increase as it approaches the center of the valve bridge 1 and decreases as it approaches the left and right ends. Here, the dimension in the vertical direction at the center of the valve bridge 1 is h ₁ , and the dimension at both left and right ends is set to h ₂ (h ₂ <h ₁ ). The shape of the rib portion 5 is a downwardly convex mountain shape with the central portion in the extending direction of the valve bridge 1 as the top portion, and is similar to a shape symmetrical in the vertical direction with the bridge body portion 1b.

[3. Action, effect]
The valve operating mechanism 10 including the valve bridge 1 is configured as described above, and has the following operations and effects.
In a state where the intake valve 7 closes the intake port 30a, the lower end surface 15a of the arm portion 15 of the rocker arm 6 and the rocker arm contact surface 3 of the valve bridge 1 are in line contact at a point D as shown by a solid line in FIG. is doing. Further, the upper end surface 13 a of the valve stem 13 of the intake valve 7 is in surface contact with the valve contact surfaces 2 at both left and right ends of the valve bridge 1.

  When the camshaft 25 rotates and the flat plate cam 26 pushes the tappet 24 upward in response, the push rod 23 and the cup end 22 push the adjustment screw fixing portion 18 of the rocker arm 6 upward, and the rocker arm 6 in FIG. Swings in the clockwise direction. Since the rocker arm 6 swings in a circular motion around the rocker shaft 18, the lower end surface 15 a of the tip formed on the arm portion 15 slides on the rocker arm contact surface 3 in the right direction while the valve bridge 1. Press down.

  The pressing force input from the arm portion 15 to the valve bridge 1 is transmitted to the valve spring 9 through the spring seat 8 and to the upper end surface 13 a of the valve stem 13. As a result, the valve spring 9 is compressed and the valve stem 13 slides downward within the stem guide 11. Therefore, the valve head 14 is pushed into the cylinder 27 and the intake port 30a is opened.

  When the lift amount of the valve head 14 is maximized and the intake port 30a is opened most greatly, the lower end surface 15a of the arm portion 15 and the rocker arm contact surface 3 are in line contact at a point E, as shown by a broken line in FIG. To do. Since the lower end surface 15a of the arm portion 15 slides in the horizontal direction on the rocker arm contact surface 3 during the valve lift process, the valve bridge 1 is pressed in the horizontal direction. 2 and the upper end surface 13a of the valve stem 13 are subjected to a horizontal thrust load.

  On the other hand, the outer end side of the valve abutment surface 2 of the valve bridge 1 is opened in the horizontal direction, that is, the bank portion 4 that supports the valve stem 13 from the outer end 1a side is not formed. A thrust load is distributed to the support portions of the left and right valve stems 13. For example, even if a thrust load is applied to one valve stem 13 and the corresponding valve contact surface 2, the valve stem 13 is allowed to move horizontally toward the outer end 1 a of the valve bridge 1, and the pair of valve stems 13 On the other hand, the center line C of the valve bridge 1 moves relatively toward the center thereof. That is, the thrust load acting on each of the left and right valve stems 13 is uniform.

In this way, by distributing the thrust load generated on the valve contact surface 2 with the rocker arm 6 swinging to the left and right, the wear amount of the valve contact surface 2 can be reduced, and the durability of the member can be reduced. Can be increased. Further, since the load is discrete for each of the left and right intake valves 7, the margin for overrun of the valve mechanism 10 can be improved.
Further, a bank portion 4 is formed at the center side of the left and right valve contact surfaces 2 and the distance F between the inner walls 4a is set to the same value as the allowable minimum distance. Regardless, the allowable minimum distance F between the pair of intake valves 7 can be reliably maintained between the valve contact surfaces 2 at the left and right ends of the valve bridge 1, and the opening / closing operation of the intake valve 7 can be guaranteed. it can.

  Since the intake valve 7 is urged upward by the valve spring 9, when the flat plate cam 26 further rotates, the tappet 24 and the push rod 23 move downward and the rocker arm 6 swings in the counterclockwise direction in FIG. At the same time, the valve bridge 1 and the valve stem 13 slide upward, and the valve head 14 closes the intake port 30a. At this time, the contact position between the lower end surface 15a of the arm portion 15 and the rocker arm contact surface 3 moves again to the point D side in FIG. 4, and a thrust load in the direction opposite to that when the intake valve 7 is opened acts. However, such a load can also be distributed to the left and right valve contact surfaces 2.

  In the present valve bridge 1, the valve contact surface 2 is composed of a semicircular surface 2a having the same radius r as the upper end surface 13a of the valve stem 13, and a rectangular surface 2b adjacent to the semicircular surface 2b. Since it is formed to have the same size as the radius r, it can be brought into contact with the entire upper end surface 13a of the valve stem 13, and the movement of the valve bridge 1 can be reliably transmitted to the intake valve 7.

  Further, for example, as compared with the case where the valve contact surface 2 is formed in a long hole shape, the longitudinal dimension of the valve bridge 1 can be shortened to the minimum necessary, and the weight of the member can be reduced. In particular, in the present valve bridge 1, by opening the outer end 1a side from the valve contact surface 2, the valve bridge 1 can be further reduced in weight. In addition, since the dimension a in the above-described embodiment is a minute value set in consideration of the construction error of the member, it can be as close to 0 as possible.

Further, the shape of the valve contact surface 2 of the valve bridge 1 can be easily processed using a tool such as an end mill, and there is an advantage that the manufacturing cost can be reduced.
Further, by providing the rib portion 5 on the lower surface of the valve bridge 1, a sectional shape advantageous in terms of stress is obtained, and the rigidity and strength of the valve bridge 1 can be improved. In particular, deformation with respect to a load in the vertical direction can be effectively suppressed. Moreover, since the dimension h ₁ in the vertical direction at the center of the rib part 5 is set to be larger than the dimension h _{2 at} the left and right ends, bending deformation in the extending direction of the valve bridge 1 is effectively suppressed. be able to.

[4. Others]
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.
In the above-described embodiment, the valve operating mechanism 10 that drives the intake valve 7 to open and close is illustrated, but the exhaust valve may be driven to open and close by the same configuration. In the above-described embodiment, the main valve mechanism 10 is applied to an OHV multi-cylinder diesel engine. However, the present embodiment may be applied to a single-cylinder gasoline engine or an OHC engine. May be. The present invention is applicable to at least a valve operating engine having a valve bridge that transmits a swinging motion transmitted from a rocker arm to a plurality of valves.

DESCRIPTION OF SYMBOLS 1 Valve bridge 1a Outer end 1b Bridge main-body part 2 Valve contact surface 2a Semicircular surface 2b Rectangular surface 3 Rocker arm contact surface 4 Bank part 4a Inner wall 5 Rib part 6 Rocker arm 7 Intake valve (a pair of valves)
DESCRIPTION OF SYMBOLS 8 Spring seat 9 Valve spring 10 Valve mechanism 11 Stem guide 12 Oil seal 13 Valve stem 13a Upper end surface 13b Tubular surface 14 Valve head 15 Arm part 15a Lower end surface 16 Housing part 17 Adjustment screw fixing | fixed part 17a Adjustment screw 18 Rocker shaft 19 Bracket 20 Rocker cover 22 Cup end 23 Push rod 24 Tappet 24a Bottom surface 25 Cam shaft 26 Flat plate cam 26a Circumferential surface 27 Cylinder 28 Cylinder block 29 Water jacket 30 Cylinder head 30a Intake port 30b Valve through hole

Claims (3)

A valve bridge of a valve operating mechanism interposed between a rocker arm and a pair of valves,
A valve abutting surface that is formed smoothly on the lower surface of each of the one end and the other end, and abuts against one and the other upper end surfaces of the pair of valves;
A rocker arm abutting surface that is formed smoothly on the central upper surface of the one end and the other end and abuts against the rocker arm;
A bank portion extending downward on the rocker arm contact surface side around each of the valve contact surfaces,
A valve bridge of a valve operating mechanism, wherein a side opposite to the rocker arm contact surface side around each of the valve contact surfaces is opened horizontally to the outer end of the valve bridge. The pair of valves are formed such that the upper end surface is circular,
Each of the valve contact surfaces
A semicircular surface formed in a semicircular shape having substantially the same radius as the upper end surfaces of the pair of valves;
A first side having a diameter on the semicircular surface, and a second side having substantially the same size as the radius of the upper end surface extending perpendicularly to the first side from both ends of the arc on the semicircular surface The valve bridge for a valve operating mechanism according to claim 1, wherein the valve bridge is formed in a rectangular shape and is formed of a rectangular surface disposed adjacent to the semicircular surface. On the lower surface between the respective valve contact surfaces, provided with a rib portion extending vertically downward,
3. The motion according to claim 1, wherein a vertical dimension of the rib portion at the center of the one end and the other end is set larger than the dimension in the vicinity of the valve contact surface. Valve bridge of the valve mechanism.

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